Spectrometric apparatus for measuring shifted spectral distributions

Abstract

This invention relates to a spectroscopic apparatus for measuring at least two spectrally shifted spectral distributions of a light beam, said apparatus comprises a dispersive element adapted to generate a spatial dispersion of the spectral components in a light beam when said dispersive element is being illuminated by said light beam; and a detector adapted to measure the intensity of at least a part of said dispersed spectral components where said apparatus further comprises an optical shifting means adapted to illuminate said dispersive element in at least two different ways, such that said light beam hits said dispersive element differently, and whereby said dispersive element generates at least two spatially shifted spatial dispersions of the spectral components in said light beam. The invention further relates to a probing system comprising said spectroscopic apparatus for measuring at least two spectrally shifted spectral distributions of a light beam, and a method for measuring at least two spectrally shifted spectral distributions of a light beam.

1 . A spectroscopic apparatus for measuring at least two spectrally shifted spectral distributions of a light beam, said apparatus comprising:
 a dispersive element adapted to generate a spatial dispersion of the spectral components in a light beam when said dispersive element is being illuminated by said light beam;   a detector adapted to measure the intensity of at least a part of said dispersed spectral components;   characterized in that said apparatus further comprises:   optical shifting means adapted to illuminate said dispersive element in at least two different ways, whereby said dispersive element generates at least two spatially shifted spatial dispersions of the spectral components in said light beam.   
   
   
       2 . A spectroscopic apparatus according to  claim 1  characterized in that said optical shifting means comprises an optical switch, a first optical path and a second optical path, where said optical switch is adapted to receive said light beam and adapted to direct said light beam into said first optical path or into said second optical path, said first optical path being adapted to illuminate said dispersive element in a first way, whereby said dispersive element generates a first spatial dispersion of the spectral components in said light beam, and said second optical path being adapted to illuminate said dispersive element in a second way, whereby said dispersive element generates a second spatial dispersion of the spectral components in said light beam, said second dispersion being spatially shifted compared to said first spatial dispersion. 
   
   
       3 . A spectroscopic apparatus according to  claim 2  characterized in that said first optical path comprises a first slit illuminated by said light beam, first collimation means receiving said light beam from said first slit, where said first collimation means is adapted to collimate said light beam such that said dispersive element in said first way is illuminated by a first collimated light beam. 
   
   
       4 . A spectroscopic apparatus according to  claim 2  or  claim 3  characterized in that said second optical path comprises a second slit illuminated by said light beam, second collimation means receiving said light beam from said second slit, where said second collimation means is adapted to collimate said light beam such that said dispersive element in said second way is illuminated by a second collimated light beam. 
   
   
       5 . A spectroscopic apparatus according to any of the preceding  claims 1 - 4  characterized in that said apparatus further comprises focusing means adapted to focus at least a part of said at least two spatially shifted spatial dispersions onto said detector. 
   
   
       6 . A spectroscopic apparatus according to any of the preceding  claims 1 - 5  characterized in that said detector is a detector comprising a number of photo detectors. 
   
   
       7 . A spectroscopic apparatus according to  claim 5  and  claim 6  characterized in that said focusing means further is adapted to focus said at least a part of said two spatially shifted spatial dispersions onto a number of said photo detectors such that each photo detector is illuminated by different spectral components when said dispersive element is illuminated in different ways. 
   
   
       8 . A probing system for analysing a light beam collected from a sample, characterized in that said probing system comprises a spectroscopic apparatus as described by  claim 1 - 7 . 
   
   
       9 . A probing system according to  claim 8  characterized in that said probing system further comprises a light source for illumination of said sample. 
   
   
       10 . A probing system according to  claim 9  or  claim 10  characterized in that said probing system further comprises an optical probe adapted to collect a light beam from said sample and adapted to direct said light beam into said spectroscopic apparatus described by  claim 1 - 7 . 
   
   
       11 . A probing system according to any of the preceding  claims 8 - 10  characterized in that said probing system further comprises processing means and storing means, said processing being adapted to store spectrally shifted spectral distributions measured by said spectroscopic apparatus in said storing means. 
   
   
       12 . A probing system according to any of the preceding  claims 8 - 11  characterized in that said processing means further is adapted to perform a SSRS method using said spectrally shifted spectral distributions. 
   
   
       13 . A method for measuring at least two spectrally shifted spectral distributions of a light beam; said method comprising the steps of:
 generating a first spatial dispersion of the spectral components in said light beam by illuminating a dispersive element by said light beam in a first way, such that said dispersive element generates a first spatial dispersion of the spectral components in said light beam;   detecting the intensity of at least a part of said first spatial dispersion using a detector;   characterized in that said method further comprises the steps of:   generating a second spatial dispersion of the spectral components in said light beam by illuminating said dispersive element by said light beam in a second way, such that said dispersive element generates a second spatial dispersion of the spectral components in said light beam, said second dispersion being spatially shifted compared to said first spatial dispersion;   detecting the intensity of at least a part of said second spatial dispersion using said detector.